Which signal answers which question?

Goal & mental model verified

Actuator exposes operational endpoints under explicit exposure/security settings. Micrometer Observation can support metrics and tracing. Low-cardinality dimensions suit metric aggregation; high-cardinality identifiers can explode metric series.

Worked example · design exercise synthesis

Observe quote latency by route template and outcome. Correlate a slow request through a trace; inspect database wait and JVM events instead of placing every policy ID in a metric label.

Engineering decision synthesis

Design signals around an operational question: errors, latency, saturation and dependency behavior. Expose only required management capabilities and restrict sensitive endpoints.

Pitfall & diagnosis synthesis

Health is not one universal status. Putting shared external outages into liveness can trigger needless restarts; readiness dependencies should reflect whether this instance can serve useful traffic.

Improve & validate synthesis

Simulate slow insurer calls and database outages. Confirm traces propagate and alerts identify the constrained boundary; measure signal cardinality and retention costs.